The largest increases were found among more advantaged families. Children living in families at or above 400 percent of the federal poverty level reported a 28.4 percent increase in disabilities over the 10-year period of the study. Researchers suggest that shifts in diagnostic criteria, overall increases in rates of certain problems including autism, increased awareness of these conditions and the need for a specific diagnosis to receive services such as early intervention may explain increased rates of disability related to neurodevelopmental or mental health conditions.

The authors conclude that documenting the changes in childhood disabilities is an important step in developing better prevention and treatment strategies and in determining how to create and deliver services to best meet the needs of all children.